Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C7/00—Coherent pavings made in situ
  • E01C7/08—Coherent pavings made in situ made of road-metal and binders
  • E01C7/18—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders
  • E01C7/26—Coherent pavings made in situ made of road-metal and binders of road-metal and bituminous binders mixed with other materials, e.g. cement, rubber, leather, fibre

Definitions

• the present invention relates to a covering for base layers, in particular according to ZTVT-StB 86, consisting of natural and / or artificial minerals and a binder mixture of bitumen and hydraulic binder.
• the invention further relates to the method for producing such coverings.
• ZTVT-StB 86 contains the additional technical regulations and guidelines for base layers in road construction, published by the Federal Ministry of Transport, Road Construction Department.
• the base layers for road construction are then divided into three classes, namely base layers without binders, base layers with hydraulic binders and base layers with bituminous binders.
• the base layers without binders are generally used as the bottom base layer. These are mixtures of mineral mixtures graded according to the regulations.
• Base layers with hydraulic binders consist of unbroken and / or broken mineral mixtures and hydraulic binders. It is a very rigid construction that does not allow any deformation.
• the disadvantage of these base layers is the very high sensitivity to cracks, which can penetrate into the bituminous ceilings above.
• Base courses with hydraulic binders are mainly used under cement-bound road surfaces.
• Base layers with bituminous binders are a mixture that consists of graded minerals and road bitumen or pitch bitumen or highly viscous road pitch as a binder. These base layers are manufactured in hot installation.
• bituminous base layers With bituminous base layers, deformations within the road construction can occur under heavy traffic loads and unfavorable influences, especially if the substructure is not sufficiently load-bearing or soft (for example, rutting).
• the advantage of bituminous base layers is that they are very flexible and therefore remain largely free of cracks.
• a method for producing a building material for base layers for road superstructure consisting of a mineral grain mixture and, based on the weight of the mineral grain mixture, 2 to 15 parts by weight of a hydraulically active filler, 1 to 5 parts by weight of bitumen as Binder and 4 to 15 parts by weight of water using mineral grain coated with bitumen, 70 to 90% by weight of the mineral grain mixture being mixed with the hydraulically active filler and the water and separately the remaining 30 to 10% by weight of the mineral grain mixture with bitumen or tar or a mixture thereof, whereupon the two mixtures are roughly mixed together.
• This process is intended to create base layers that have an approximately high load-bearing capacity like cement floor, but in any case have the load-bearing capacity of the hydraulically consolidated mineral mixture and have a self-healing ability that is characteristic of the construction methods with bitumen or tar.
• the hydraulic setting is slowed down by the addition of bitumen, so that no large, closed, formed plates can arise, which also result in large tears when torn apart. Rather, a large number of small, irregular cracks are deliberately sought, but these are partially bonded to one another by the bitumen.
• the adhesive force must be maintained, which gives the building material a self-healing ability.
• a maximum of 30% by weight of the grains of the mineral mixture may be coated with the bitumen, since a building material in which the coating of the mineral material with the bitumen binder exceeds the entire 30% by weight no longer achieves the task can. This method has obviously not proven itself in practice, so that the patent was dropped again relatively early after it was granted.
• the manufacture of a semi-rigid covering for traffic areas according to DE-AS 26 23 556 is based on a similar principle, in which a void-rich supporting structure made of a mineral mixture coated with bituminous binders is used, the cavities of which are completely filled with a cement mortar with a binder additive and in which the cement mortar contains a bitumen emulsion as a binder additive.
• a void-rich, coarse-grained mineral mixture is pre-coated with bitumen, tar or bituminous binders modified with additives and a mortar is made separately from a sand mixture with the addition of water, cement and a bitumen emulsion, then the whole is mixed, transported, installed and condensed.
• the pores of the coarse-grained portion coated with bitumen are filled with a hydraulically setting, finely divided component. No information is available on the amounts of the binders used.
• bitumen emulsion-asphalt mixtures with mixed binding material for road construction are known, in which the cationic bitumen emulsion and an alkaline earth metal oxide and / or hydroxide containing hydraulic powder are used together with conventional mineral additives.
• the asphalt mixtures described therein contain 0.5 to 8% by weight of hydraulic powder and 2.5 to 10% by weight of cationic bitumen emulsion and 82 to 97% by weight of conventional mineral additives. From the examples it can be seen that at least 7% bitumen emulsion and at least 3% alkaline ash were used and that road surfaces were then produced therefrom.
• the effect of this mixture is that the free alkali earth metal oxide or hydroxide content of the hydraulic powder improves the adhesiveness of the bitumen and thereby increases the initial cohesion of the structure.
• the mineral additive is therefore always premixed dry with the basic ash and only then sprayed with the cationic bitumen emulsion. Mixing only took up to 42 seconds. The mixture was then applied and compacted.
• the object of the invention is to make base layers, in particular base layers in accordance with ZTVT-StB 86, better, cheaper, more durable and yet easy to produce, the disadvantages of base layers with hydraulic binders and base layers with bituminous binders being avoided, but retaining the advantages thereof should be.
• the content of bitumen and hydraulic binder is 1.0 to 3.0% by weight, the content of both together is at least 3% by weight. is and
• the original water content approximately corresponds to the water content that enables the densest storage (measured according to Proctor (DIN 18127)).
• the content of bitumen and hydraulic binder is preferably 2.0 to 2.5% by weight.
• the total water content is measured according to the Proctor method (DIN 18127). Water contents are preferably used which are 0 to 20%, based on the water content, below the optimal water content according to Proctor.
• the anionic aqueous bitumen emulsion which, in contrast to the mixture according to DE-OS 32 45 068, the cationic bitumen emulsion, is not broken by the addition of the alkaline hydraulic binders.
• the water content used according to the invention which approximately corresponds to the water content which enables the densest storage according to Proctor, is required in order to make the mixture installable and sufficiently compressible on the construction site.
• the mixture can therefore be premixed, transported, installed and compacted in the usual periods of time without the need for special precautionary measures or very rapid work.
• the full load-bearing capacity of the material is only achieved after the hydraulic binding agent has set, but the built-in and compacted layer has sufficient load-bearing capacity to absorb the stress caused by construction site traffic and to ensure construction progress.
• a particular advantage of the base layers according to the invention is that they make do with relatively small amounts of binders, namely 3 to 6% by weight, preferably 4 to 5% by weight, based on the base layer mixture.
• base layers are formed which, after the hydraulic binder has set, have Marshall stabilities and Marshall flow values which correspond to the requirements of ZTVT-StB-86 table 4.2 for bituminous base layer mix of the type CS for special loads.
• Another advantage of the method according to the invention is that considerable amounts of recycled building materials can be used as minerals. This material can be added to the minerals alone or in any quantity, provided the particle size distribution, shape and other requirements comply with the regulations of ZTVT-StB 86.
• the mixtures can be processed in conventional forced or free-fall mixers.
• the paving is carried out using conventional pavers or the concrete paving train.
• the compression takes place in the usual way by means of a built-in device and / or roller insert.
• the base layers obtained in this way are passable and resilient for the further expansion of the pavement.
• a base course mix of 0/22 mm is used.
• Limestone was used as a mineral with the composition Limestone grit 65% by weight Limestone crushed stone 30% by weight and Limestone flour 5% by weight.
• 2.0% by weight of bitumen was added to this mixture in the form of a 50% bitumen emulsion, anionic, with a viscosity of 4 mm / 20 ° C.: 20 to 30 seconds and 2.0% by weight of PZ 35 cement F.
• the amount of water was measured so that it was 10% below the amount that allows the tightest storage, measured according to Proctor (DIN 18127).
• the base layer obtained therefrom showed a Marshall stability of 12.0 kN and a Marshall flow value of 2.3 mm after 28 days. This material meets the requirements of ZTVT-StB-86 table 4.2 for bituminous base layer mix of type CS for special demands.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Road Paving Structures (AREA)
• Outer Garments And Coats (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6342060

Family Applications (1)

Country Status (3)

Cited By (5)

Family Cites Families (4)

• 1988
  • 1988-11-01 DE DE8888118172T patent/DE3864988D1/de not_active Expired - Lifetime
  • 1988-11-01 EP EP88118172A patent/EP0319702B1/fr not_active Expired - Lifetime
  • 1988-11-01 AT AT88118172T patent/ATE67540T1/de not_active IP Right Cessation

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